summaryrefslogtreecommitdiffstats
path: root/kernel/drivers/usb/serial/cypress_m8.c
diff options
context:
space:
mode:
authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/drivers/usb/serial/cypress_m8.c
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/drivers/usb/serial/cypress_m8.c')
-rw-r--r--kernel/drivers/usb/serial/cypress_m8.c1267
1 files changed, 1267 insertions, 0 deletions
diff --git a/kernel/drivers/usb/serial/cypress_m8.c b/kernel/drivers/usb/serial/cypress_m8.c
new file mode 100644
index 000000000..01bf53392
--- /dev/null
+++ b/kernel/drivers/usb/serial/cypress_m8.c
@@ -0,0 +1,1267 @@
+/*
+ * USB Cypress M8 driver
+ *
+ * Copyright (C) 2004
+ * Lonnie Mendez (dignome@gmail.com)
+ * Copyright (C) 2003,2004
+ * Neil Whelchel (koyama@firstlight.net)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * See Documentation/usb/usb-serial.txt for more information on using this
+ * driver
+ *
+ * See http://geocities.com/i0xox0i for information on this driver and the
+ * earthmate usb device.
+ */
+
+/* Thanks to Neil Whelchel for writing the first cypress m8 implementation
+ for linux. */
+/* Thanks to cypress for providing references for the hid reports. */
+/* Thanks to Jiang Zhang for providing links and for general help. */
+/* Code originates and was built up from ftdi_sio, belkin, pl2303 and others.*/
+
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_driver.h>
+#include <linux/tty_flip.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/spinlock.h>
+#include <linux/usb.h>
+#include <linux/usb/serial.h>
+#include <linux/serial.h>
+#include <linux/kfifo.h>
+#include <linux/delay.h>
+#include <linux/uaccess.h>
+#include <asm/unaligned.h>
+
+#include "cypress_m8.h"
+
+
+static bool stats;
+static int interval;
+static bool unstable_bauds;
+
+#define DRIVER_AUTHOR "Lonnie Mendez <dignome@gmail.com>, Neil Whelchel <koyama@firstlight.net>"
+#define DRIVER_DESC "Cypress USB to Serial Driver"
+
+/* write buffer size defines */
+#define CYPRESS_BUF_SIZE 1024
+
+static const struct usb_device_id id_table_earthmate[] = {
+ { USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB) },
+ { USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB_LT20) },
+ { } /* Terminating entry */
+};
+
+static const struct usb_device_id id_table_cyphidcomrs232[] = {
+ { USB_DEVICE(VENDOR_ID_CYPRESS, PRODUCT_ID_CYPHIDCOM) },
+ { USB_DEVICE(VENDOR_ID_POWERCOM, PRODUCT_ID_UPS) },
+ { USB_DEVICE(VENDOR_ID_FRWD, PRODUCT_ID_CYPHIDCOM_FRWD) },
+ { } /* Terminating entry */
+};
+
+static const struct usb_device_id id_table_nokiaca42v2[] = {
+ { USB_DEVICE(VENDOR_ID_DAZZLE, PRODUCT_ID_CA42) },
+ { } /* Terminating entry */
+};
+
+static const struct usb_device_id id_table_combined[] = {
+ { USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB) },
+ { USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB_LT20) },
+ { USB_DEVICE(VENDOR_ID_CYPRESS, PRODUCT_ID_CYPHIDCOM) },
+ { USB_DEVICE(VENDOR_ID_POWERCOM, PRODUCT_ID_UPS) },
+ { USB_DEVICE(VENDOR_ID_FRWD, PRODUCT_ID_CYPHIDCOM_FRWD) },
+ { USB_DEVICE(VENDOR_ID_DAZZLE, PRODUCT_ID_CA42) },
+ { } /* Terminating entry */
+};
+
+MODULE_DEVICE_TABLE(usb, id_table_combined);
+
+enum packet_format {
+ packet_format_1, /* b0:status, b1:payload count */
+ packet_format_2 /* b0[7:3]:status, b0[2:0]:payload count */
+};
+
+struct cypress_private {
+ spinlock_t lock; /* private lock */
+ int chiptype; /* identifier of device, for quirks/etc */
+ int bytes_in; /* used for statistics */
+ int bytes_out; /* used for statistics */
+ int cmd_count; /* used for statistics */
+ int cmd_ctrl; /* always set this to 1 before issuing a command */
+ struct kfifo write_fifo; /* write fifo */
+ int write_urb_in_use; /* write urb in use indicator */
+ int write_urb_interval; /* interval to use for write urb */
+ int read_urb_interval; /* interval to use for read urb */
+ int comm_is_ok; /* true if communication is (still) ok */
+ int termios_initialized;
+ __u8 line_control; /* holds dtr / rts value */
+ __u8 current_status; /* received from last read - info on dsr,cts,cd,ri,etc */
+ __u8 current_config; /* stores the current configuration byte */
+ __u8 rx_flags; /* throttling - used from whiteheat/ftdi_sio */
+ enum packet_format pkt_fmt; /* format to use for packet send / receive */
+ int get_cfg_unsafe; /* If true, the CYPRESS_GET_CONFIG is unsafe */
+ int baud_rate; /* stores current baud rate in
+ integer form */
+ int isthrottled; /* if throttled, discard reads */
+ char prev_status; /* used for TIOCMIWAIT */
+ /* we pass a pointer to this as the argument sent to
+ cypress_set_termios old_termios */
+ struct ktermios tmp_termios; /* stores the old termios settings */
+};
+
+/* function prototypes for the Cypress USB to serial device */
+static int cypress_earthmate_port_probe(struct usb_serial_port *port);
+static int cypress_hidcom_port_probe(struct usb_serial_port *port);
+static int cypress_ca42v2_port_probe(struct usb_serial_port *port);
+static int cypress_port_remove(struct usb_serial_port *port);
+static int cypress_open(struct tty_struct *tty, struct usb_serial_port *port);
+static void cypress_close(struct usb_serial_port *port);
+static void cypress_dtr_rts(struct usb_serial_port *port, int on);
+static int cypress_write(struct tty_struct *tty, struct usb_serial_port *port,
+ const unsigned char *buf, int count);
+static void cypress_send(struct usb_serial_port *port);
+static int cypress_write_room(struct tty_struct *tty);
+static void cypress_set_termios(struct tty_struct *tty,
+ struct usb_serial_port *port, struct ktermios *old);
+static int cypress_tiocmget(struct tty_struct *tty);
+static int cypress_tiocmset(struct tty_struct *tty,
+ unsigned int set, unsigned int clear);
+static int cypress_chars_in_buffer(struct tty_struct *tty);
+static void cypress_throttle(struct tty_struct *tty);
+static void cypress_unthrottle(struct tty_struct *tty);
+static void cypress_set_dead(struct usb_serial_port *port);
+static void cypress_read_int_callback(struct urb *urb);
+static void cypress_write_int_callback(struct urb *urb);
+
+static struct usb_serial_driver cypress_earthmate_device = {
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = "earthmate",
+ },
+ .description = "DeLorme Earthmate USB",
+ .id_table = id_table_earthmate,
+ .num_ports = 1,
+ .port_probe = cypress_earthmate_port_probe,
+ .port_remove = cypress_port_remove,
+ .open = cypress_open,
+ .close = cypress_close,
+ .dtr_rts = cypress_dtr_rts,
+ .write = cypress_write,
+ .write_room = cypress_write_room,
+ .set_termios = cypress_set_termios,
+ .tiocmget = cypress_tiocmget,
+ .tiocmset = cypress_tiocmset,
+ .tiocmiwait = usb_serial_generic_tiocmiwait,
+ .chars_in_buffer = cypress_chars_in_buffer,
+ .throttle = cypress_throttle,
+ .unthrottle = cypress_unthrottle,
+ .read_int_callback = cypress_read_int_callback,
+ .write_int_callback = cypress_write_int_callback,
+};
+
+static struct usb_serial_driver cypress_hidcom_device = {
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = "cyphidcom",
+ },
+ .description = "HID->COM RS232 Adapter",
+ .id_table = id_table_cyphidcomrs232,
+ .num_ports = 1,
+ .port_probe = cypress_hidcom_port_probe,
+ .port_remove = cypress_port_remove,
+ .open = cypress_open,
+ .close = cypress_close,
+ .dtr_rts = cypress_dtr_rts,
+ .write = cypress_write,
+ .write_room = cypress_write_room,
+ .set_termios = cypress_set_termios,
+ .tiocmget = cypress_tiocmget,
+ .tiocmset = cypress_tiocmset,
+ .tiocmiwait = usb_serial_generic_tiocmiwait,
+ .chars_in_buffer = cypress_chars_in_buffer,
+ .throttle = cypress_throttle,
+ .unthrottle = cypress_unthrottle,
+ .read_int_callback = cypress_read_int_callback,
+ .write_int_callback = cypress_write_int_callback,
+};
+
+static struct usb_serial_driver cypress_ca42v2_device = {
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = "nokiaca42v2",
+ },
+ .description = "Nokia CA-42 V2 Adapter",
+ .id_table = id_table_nokiaca42v2,
+ .num_ports = 1,
+ .port_probe = cypress_ca42v2_port_probe,
+ .port_remove = cypress_port_remove,
+ .open = cypress_open,
+ .close = cypress_close,
+ .dtr_rts = cypress_dtr_rts,
+ .write = cypress_write,
+ .write_room = cypress_write_room,
+ .set_termios = cypress_set_termios,
+ .tiocmget = cypress_tiocmget,
+ .tiocmset = cypress_tiocmset,
+ .tiocmiwait = usb_serial_generic_tiocmiwait,
+ .chars_in_buffer = cypress_chars_in_buffer,
+ .throttle = cypress_throttle,
+ .unthrottle = cypress_unthrottle,
+ .read_int_callback = cypress_read_int_callback,
+ .write_int_callback = cypress_write_int_callback,
+};
+
+static struct usb_serial_driver * const serial_drivers[] = {
+ &cypress_earthmate_device, &cypress_hidcom_device,
+ &cypress_ca42v2_device, NULL
+};
+
+/*****************************************************************************
+ * Cypress serial helper functions
+ *****************************************************************************/
+
+/* FRWD Dongle hidcom needs to skip reset and speed checks */
+static inline bool is_frwd(struct usb_device *dev)
+{
+ return ((le16_to_cpu(dev->descriptor.idVendor) == VENDOR_ID_FRWD) &&
+ (le16_to_cpu(dev->descriptor.idProduct) == PRODUCT_ID_CYPHIDCOM_FRWD));
+}
+
+static int analyze_baud_rate(struct usb_serial_port *port, speed_t new_rate)
+{
+ struct cypress_private *priv;
+ priv = usb_get_serial_port_data(port);
+
+ if (unstable_bauds)
+ return new_rate;
+
+ /* FRWD Dongle uses 115200 bps */
+ if (is_frwd(port->serial->dev))
+ return new_rate;
+
+ /*
+ * The general purpose firmware for the Cypress M8 allows for
+ * a maximum speed of 57600bps (I have no idea whether DeLorme
+ * chose to use the general purpose firmware or not), if you
+ * need to modify this speed setting for your own project
+ * please add your own chiptype and modify the code likewise.
+ * The Cypress HID->COM device will work successfully up to
+ * 115200bps (but the actual throughput is around 3kBps).
+ */
+ if (port->serial->dev->speed == USB_SPEED_LOW) {
+ /*
+ * Mike Isely <isely@pobox.com> 2-Feb-2008: The
+ * Cypress app note that describes this mechanism
+ * states the the low-speed part can't handle more
+ * than 800 bytes/sec, in which case 4800 baud is the
+ * safest speed for a part like that.
+ */
+ if (new_rate > 4800) {
+ dev_dbg(&port->dev,
+ "%s - failed setting baud rate, device incapable speed %d\n",
+ __func__, new_rate);
+ return -1;
+ }
+ }
+ switch (priv->chiptype) {
+ case CT_EARTHMATE:
+ if (new_rate <= 600) {
+ /* 300 and 600 baud rates are supported under
+ * the generic firmware, but are not used with
+ * NMEA and SiRF protocols */
+ dev_dbg(&port->dev,
+ "%s - failed setting baud rate, unsupported speed of %d on Earthmate GPS\n",
+ __func__, new_rate);
+ return -1;
+ }
+ break;
+ default:
+ break;
+ }
+ return new_rate;
+}
+
+
+/* This function can either set or retrieve the current serial line settings */
+static int cypress_serial_control(struct tty_struct *tty,
+ struct usb_serial_port *port, speed_t baud_rate, int data_bits,
+ int stop_bits, int parity_enable, int parity_type, int reset,
+ int cypress_request_type)
+{
+ int new_baudrate = 0, retval = 0, tries = 0;
+ struct cypress_private *priv;
+ struct device *dev = &port->dev;
+ u8 *feature_buffer;
+ const unsigned int feature_len = 5;
+ unsigned long flags;
+
+ priv = usb_get_serial_port_data(port);
+
+ if (!priv->comm_is_ok)
+ return -ENODEV;
+
+ feature_buffer = kcalloc(feature_len, sizeof(u8), GFP_KERNEL);
+ if (!feature_buffer)
+ return -ENOMEM;
+
+ switch (cypress_request_type) {
+ case CYPRESS_SET_CONFIG:
+ /* 0 means 'Hang up' so doesn't change the true bit rate */
+ new_baudrate = priv->baud_rate;
+ if (baud_rate && baud_rate != priv->baud_rate) {
+ dev_dbg(dev, "%s - baud rate is changing\n", __func__);
+ retval = analyze_baud_rate(port, baud_rate);
+ if (retval >= 0) {
+ new_baudrate = retval;
+ dev_dbg(dev, "%s - New baud rate set to %d\n",
+ __func__, new_baudrate);
+ }
+ }
+ dev_dbg(dev, "%s - baud rate is being sent as %d\n", __func__,
+ new_baudrate);
+
+ /* fill the feature_buffer with new configuration */
+ put_unaligned_le32(new_baudrate, feature_buffer);
+ feature_buffer[4] |= data_bits; /* assign data bits in 2 bit space ( max 3 ) */
+ /* 1 bit gap */
+ feature_buffer[4] |= (stop_bits << 3); /* assign stop bits in 1 bit space */
+ feature_buffer[4] |= (parity_enable << 4); /* assign parity flag in 1 bit space */
+ feature_buffer[4] |= (parity_type << 5); /* assign parity type in 1 bit space */
+ /* 1 bit gap */
+ feature_buffer[4] |= (reset << 7); /* assign reset at end of byte, 1 bit space */
+
+ dev_dbg(dev, "%s - device is being sent this feature report:\n", __func__);
+ dev_dbg(dev, "%s - %02X - %02X - %02X - %02X - %02X\n", __func__,
+ feature_buffer[0], feature_buffer[1],
+ feature_buffer[2], feature_buffer[3],
+ feature_buffer[4]);
+
+ do {
+ retval = usb_control_msg(port->serial->dev,
+ usb_sndctrlpipe(port->serial->dev, 0),
+ HID_REQ_SET_REPORT,
+ USB_DIR_OUT | USB_RECIP_INTERFACE | USB_TYPE_CLASS,
+ 0x0300, 0, feature_buffer,
+ feature_len, 500);
+
+ if (tries++ >= 3)
+ break;
+
+ } while (retval != feature_len &&
+ retval != -ENODEV);
+
+ if (retval != feature_len) {
+ dev_err(dev, "%s - failed sending serial line settings - %d\n",
+ __func__, retval);
+ cypress_set_dead(port);
+ } else {
+ spin_lock_irqsave(&priv->lock, flags);
+ priv->baud_rate = new_baudrate;
+ priv->current_config = feature_buffer[4];
+ spin_unlock_irqrestore(&priv->lock, flags);
+ /* If we asked for a speed change encode it */
+ if (baud_rate)
+ tty_encode_baud_rate(tty,
+ new_baudrate, new_baudrate);
+ }
+ break;
+ case CYPRESS_GET_CONFIG:
+ if (priv->get_cfg_unsafe) {
+ /* Not implemented for this device,
+ and if we try to do it we're likely
+ to crash the hardware. */
+ retval = -ENOTTY;
+ goto out;
+ }
+ dev_dbg(dev, "%s - retreiving serial line settings\n", __func__);
+ do {
+ retval = usb_control_msg(port->serial->dev,
+ usb_rcvctrlpipe(port->serial->dev, 0),
+ HID_REQ_GET_REPORT,
+ USB_DIR_IN | USB_RECIP_INTERFACE | USB_TYPE_CLASS,
+ 0x0300, 0, feature_buffer,
+ feature_len, 500);
+
+ if (tries++ >= 3)
+ break;
+ } while (retval != feature_len
+ && retval != -ENODEV);
+
+ if (retval != feature_len) {
+ dev_err(dev, "%s - failed to retrieve serial line settings - %d\n",
+ __func__, retval);
+ cypress_set_dead(port);
+ goto out;
+ } else {
+ spin_lock_irqsave(&priv->lock, flags);
+ /* store the config in one byte, and later
+ use bit masks to check values */
+ priv->current_config = feature_buffer[4];
+ priv->baud_rate = get_unaligned_le32(feature_buffer);
+ spin_unlock_irqrestore(&priv->lock, flags);
+ }
+ }
+ spin_lock_irqsave(&priv->lock, flags);
+ ++priv->cmd_count;
+ spin_unlock_irqrestore(&priv->lock, flags);
+out:
+ kfree(feature_buffer);
+ return retval;
+} /* cypress_serial_control */
+
+
+static void cypress_set_dead(struct usb_serial_port *port)
+{
+ struct cypress_private *priv = usb_get_serial_port_data(port);
+ unsigned long flags;
+
+ spin_lock_irqsave(&priv->lock, flags);
+ if (!priv->comm_is_ok) {
+ spin_unlock_irqrestore(&priv->lock, flags);
+ return;
+ }
+ priv->comm_is_ok = 0;
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ dev_err(&port->dev, "cypress_m8 suspending failing port %d - "
+ "interval might be too short\n", port->port_number);
+}
+
+
+/*****************************************************************************
+ * Cypress serial driver functions
+ *****************************************************************************/
+
+
+static int cypress_generic_port_probe(struct usb_serial_port *port)
+{
+ struct usb_serial *serial = port->serial;
+ struct cypress_private *priv;
+
+ priv = kzalloc(sizeof(struct cypress_private), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->comm_is_ok = !0;
+ spin_lock_init(&priv->lock);
+ if (kfifo_alloc(&priv->write_fifo, CYPRESS_BUF_SIZE, GFP_KERNEL)) {
+ kfree(priv);
+ return -ENOMEM;
+ }
+
+ /* Skip reset for FRWD device. It is a workaound:
+ device hangs if it receives SET_CONFIGURE in Configured
+ state. */
+ if (!is_frwd(serial->dev))
+ usb_reset_configuration(serial->dev);
+
+ priv->cmd_ctrl = 0;
+ priv->line_control = 0;
+ priv->termios_initialized = 0;
+ priv->rx_flags = 0;
+ /* Default packet format setting is determined by packet size.
+ Anything with a size larger then 9 must have a separate
+ count field since the 3 bit count field is otherwise too
+ small. Otherwise we can use the slightly more compact
+ format. This is in accordance with the cypress_m8 serial
+ converter app note. */
+ if (port->interrupt_out_size > 9)
+ priv->pkt_fmt = packet_format_1;
+ else
+ priv->pkt_fmt = packet_format_2;
+
+ if (interval > 0) {
+ priv->write_urb_interval = interval;
+ priv->read_urb_interval = interval;
+ dev_dbg(&port->dev, "%s - read & write intervals forced to %d\n",
+ __func__, interval);
+ } else {
+ priv->write_urb_interval = port->interrupt_out_urb->interval;
+ priv->read_urb_interval = port->interrupt_in_urb->interval;
+ dev_dbg(&port->dev, "%s - intervals: read=%d write=%d\n",
+ __func__, priv->read_urb_interval,
+ priv->write_urb_interval);
+ }
+ usb_set_serial_port_data(port, priv);
+
+ port->port.drain_delay = 256;
+
+ return 0;
+}
+
+
+static int cypress_earthmate_port_probe(struct usb_serial_port *port)
+{
+ struct usb_serial *serial = port->serial;
+ struct cypress_private *priv;
+ int ret;
+
+ ret = cypress_generic_port_probe(port);
+ if (ret) {
+ dev_dbg(&port->dev, "%s - Failed setting up port\n", __func__);
+ return ret;
+ }
+
+ priv = usb_get_serial_port_data(port);
+ priv->chiptype = CT_EARTHMATE;
+ /* All Earthmate devices use the separated-count packet
+ format! Idiotic. */
+ priv->pkt_fmt = packet_format_1;
+ if (serial->dev->descriptor.idProduct !=
+ cpu_to_le16(PRODUCT_ID_EARTHMATEUSB)) {
+ /* The old original USB Earthmate seemed able to
+ handle GET_CONFIG requests; everything they've
+ produced since that time crashes if this command is
+ attempted :-( */
+ dev_dbg(&port->dev,
+ "%s - Marking this device as unsafe for GET_CONFIG commands\n",
+ __func__);
+ priv->get_cfg_unsafe = !0;
+ }
+
+ return 0;
+}
+
+static int cypress_hidcom_port_probe(struct usb_serial_port *port)
+{
+ struct cypress_private *priv;
+ int ret;
+
+ ret = cypress_generic_port_probe(port);
+ if (ret) {
+ dev_dbg(&port->dev, "%s - Failed setting up port\n", __func__);
+ return ret;
+ }
+
+ priv = usb_get_serial_port_data(port);
+ priv->chiptype = CT_CYPHIDCOM;
+
+ return 0;
+}
+
+static int cypress_ca42v2_port_probe(struct usb_serial_port *port)
+{
+ struct cypress_private *priv;
+ int ret;
+
+ ret = cypress_generic_port_probe(port);
+ if (ret) {
+ dev_dbg(&port->dev, "%s - Failed setting up port\n", __func__);
+ return ret;
+ }
+
+ priv = usb_get_serial_port_data(port);
+ priv->chiptype = CT_CA42V2;
+
+ return 0;
+}
+
+static int cypress_port_remove(struct usb_serial_port *port)
+{
+ struct cypress_private *priv;
+
+ priv = usb_get_serial_port_data(port);
+
+ kfifo_free(&priv->write_fifo);
+ kfree(priv);
+
+ return 0;
+}
+
+static int cypress_open(struct tty_struct *tty, struct usb_serial_port *port)
+{
+ struct cypress_private *priv = usb_get_serial_port_data(port);
+ struct usb_serial *serial = port->serial;
+ unsigned long flags;
+ int result = 0;
+
+ if (!priv->comm_is_ok)
+ return -EIO;
+
+ /* clear halts before open */
+ usb_clear_halt(serial->dev, 0x81);
+ usb_clear_halt(serial->dev, 0x02);
+
+ spin_lock_irqsave(&priv->lock, flags);
+ /* reset read/write statistics */
+ priv->bytes_in = 0;
+ priv->bytes_out = 0;
+ priv->cmd_count = 0;
+ priv->rx_flags = 0;
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ /* Set termios */
+ cypress_send(port);
+
+ if (tty)
+ cypress_set_termios(tty, port, &priv->tmp_termios);
+
+ /* setup the port and start reading from the device */
+ if (!port->interrupt_in_urb) {
+ dev_err(&port->dev, "%s - interrupt_in_urb is empty!\n",
+ __func__);
+ return -1;
+ }
+
+ usb_fill_int_urb(port->interrupt_in_urb, serial->dev,
+ usb_rcvintpipe(serial->dev, port->interrupt_in_endpointAddress),
+ port->interrupt_in_urb->transfer_buffer,
+ port->interrupt_in_urb->transfer_buffer_length,
+ cypress_read_int_callback, port, priv->read_urb_interval);
+ result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
+
+ if (result) {
+ dev_err(&port->dev,
+ "%s - failed submitting read urb, error %d\n",
+ __func__, result);
+ cypress_set_dead(port);
+ }
+
+ return result;
+} /* cypress_open */
+
+static void cypress_dtr_rts(struct usb_serial_port *port, int on)
+{
+ struct cypress_private *priv = usb_get_serial_port_data(port);
+ /* drop dtr and rts */
+ spin_lock_irq(&priv->lock);
+ if (on == 0)
+ priv->line_control = 0;
+ else
+ priv->line_control = CONTROL_DTR | CONTROL_RTS;
+ priv->cmd_ctrl = 1;
+ spin_unlock_irq(&priv->lock);
+ cypress_write(NULL, port, NULL, 0);
+}
+
+static void cypress_close(struct usb_serial_port *port)
+{
+ struct cypress_private *priv = usb_get_serial_port_data(port);
+ unsigned long flags;
+
+ spin_lock_irqsave(&priv->lock, flags);
+ kfifo_reset_out(&priv->write_fifo);
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ dev_dbg(&port->dev, "%s - stopping urbs\n", __func__);
+ usb_kill_urb(port->interrupt_in_urb);
+ usb_kill_urb(port->interrupt_out_urb);
+
+ if (stats)
+ dev_info(&port->dev, "Statistics: %d Bytes In | %d Bytes Out | %d Commands Issued\n",
+ priv->bytes_in, priv->bytes_out, priv->cmd_count);
+} /* cypress_close */
+
+
+static int cypress_write(struct tty_struct *tty, struct usb_serial_port *port,
+ const unsigned char *buf, int count)
+{
+ struct cypress_private *priv = usb_get_serial_port_data(port);
+
+ dev_dbg(&port->dev, "%s - %d bytes\n", __func__, count);
+
+ /* line control commands, which need to be executed immediately,
+ are not put into the buffer for obvious reasons.
+ */
+ if (priv->cmd_ctrl) {
+ count = 0;
+ goto finish;
+ }
+
+ if (!count)
+ return count;
+
+ count = kfifo_in_locked(&priv->write_fifo, buf, count, &priv->lock);
+
+finish:
+ cypress_send(port);
+
+ return count;
+} /* cypress_write */
+
+
+static void cypress_send(struct usb_serial_port *port)
+{
+ int count = 0, result, offset, actual_size;
+ struct cypress_private *priv = usb_get_serial_port_data(port);
+ struct device *dev = &port->dev;
+ unsigned long flags;
+
+ if (!priv->comm_is_ok)
+ return;
+
+ dev_dbg(dev, "%s - interrupt out size is %d\n", __func__,
+ port->interrupt_out_size);
+
+ spin_lock_irqsave(&priv->lock, flags);
+ if (priv->write_urb_in_use) {
+ dev_dbg(dev, "%s - can't write, urb in use\n", __func__);
+ spin_unlock_irqrestore(&priv->lock, flags);
+ return;
+ }
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ /* clear buffer */
+ memset(port->interrupt_out_urb->transfer_buffer, 0,
+ port->interrupt_out_size);
+
+ spin_lock_irqsave(&priv->lock, flags);
+ switch (priv->pkt_fmt) {
+ default:
+ case packet_format_1:
+ /* this is for the CY7C64013... */
+ offset = 2;
+ port->interrupt_out_buffer[0] = priv->line_control;
+ break;
+ case packet_format_2:
+ /* this is for the CY7C63743... */
+ offset = 1;
+ port->interrupt_out_buffer[0] = priv->line_control;
+ break;
+ }
+
+ if (priv->line_control & CONTROL_RESET)
+ priv->line_control &= ~CONTROL_RESET;
+
+ if (priv->cmd_ctrl) {
+ priv->cmd_count++;
+ dev_dbg(dev, "%s - line control command being issued\n", __func__);
+ spin_unlock_irqrestore(&priv->lock, flags);
+ goto send;
+ } else
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ count = kfifo_out_locked(&priv->write_fifo,
+ &port->interrupt_out_buffer[offset],
+ port->interrupt_out_size - offset,
+ &priv->lock);
+ if (count == 0)
+ return;
+
+ switch (priv->pkt_fmt) {
+ default:
+ case packet_format_1:
+ port->interrupt_out_buffer[1] = count;
+ break;
+ case packet_format_2:
+ port->interrupt_out_buffer[0] |= count;
+ }
+
+ dev_dbg(dev, "%s - count is %d\n", __func__, count);
+
+send:
+ spin_lock_irqsave(&priv->lock, flags);
+ priv->write_urb_in_use = 1;
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ if (priv->cmd_ctrl)
+ actual_size = 1;
+ else
+ actual_size = count +
+ (priv->pkt_fmt == packet_format_1 ? 2 : 1);
+
+ usb_serial_debug_data(dev, __func__, port->interrupt_out_size,
+ port->interrupt_out_urb->transfer_buffer);
+
+ usb_fill_int_urb(port->interrupt_out_urb, port->serial->dev,
+ usb_sndintpipe(port->serial->dev, port->interrupt_out_endpointAddress),
+ port->interrupt_out_buffer, port->interrupt_out_size,
+ cypress_write_int_callback, port, priv->write_urb_interval);
+ result = usb_submit_urb(port->interrupt_out_urb, GFP_ATOMIC);
+ if (result) {
+ dev_err_console(port,
+ "%s - failed submitting write urb, error %d\n",
+ __func__, result);
+ priv->write_urb_in_use = 0;
+ cypress_set_dead(port);
+ }
+
+ spin_lock_irqsave(&priv->lock, flags);
+ if (priv->cmd_ctrl)
+ priv->cmd_ctrl = 0;
+
+ /* do not count the line control and size bytes */
+ priv->bytes_out += count;
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ usb_serial_port_softint(port);
+} /* cypress_send */
+
+
+/* returns how much space is available in the soft buffer */
+static int cypress_write_room(struct tty_struct *tty)
+{
+ struct usb_serial_port *port = tty->driver_data;
+ struct cypress_private *priv = usb_get_serial_port_data(port);
+ int room = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&priv->lock, flags);
+ room = kfifo_avail(&priv->write_fifo);
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ dev_dbg(&port->dev, "%s - returns %d\n", __func__, room);
+ return room;
+}
+
+
+static int cypress_tiocmget(struct tty_struct *tty)
+{
+ struct usb_serial_port *port = tty->driver_data;
+ struct cypress_private *priv = usb_get_serial_port_data(port);
+ __u8 status, control;
+ unsigned int result = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&priv->lock, flags);
+ control = priv->line_control;
+ status = priv->current_status;
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ result = ((control & CONTROL_DTR) ? TIOCM_DTR : 0)
+ | ((control & CONTROL_RTS) ? TIOCM_RTS : 0)
+ | ((status & UART_CTS) ? TIOCM_CTS : 0)
+ | ((status & UART_DSR) ? TIOCM_DSR : 0)
+ | ((status & UART_RI) ? TIOCM_RI : 0)
+ | ((status & UART_CD) ? TIOCM_CD : 0);
+
+ dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
+
+ return result;
+}
+
+
+static int cypress_tiocmset(struct tty_struct *tty,
+ unsigned int set, unsigned int clear)
+{
+ struct usb_serial_port *port = tty->driver_data;
+ struct cypress_private *priv = usb_get_serial_port_data(port);
+ unsigned long flags;
+
+ spin_lock_irqsave(&priv->lock, flags);
+ if (set & TIOCM_RTS)
+ priv->line_control |= CONTROL_RTS;
+ if (set & TIOCM_DTR)
+ priv->line_control |= CONTROL_DTR;
+ if (clear & TIOCM_RTS)
+ priv->line_control &= ~CONTROL_RTS;
+ if (clear & TIOCM_DTR)
+ priv->line_control &= ~CONTROL_DTR;
+ priv->cmd_ctrl = 1;
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ return cypress_write(tty, port, NULL, 0);
+}
+
+static void cypress_set_termios(struct tty_struct *tty,
+ struct usb_serial_port *port, struct ktermios *old_termios)
+{
+ struct cypress_private *priv = usb_get_serial_port_data(port);
+ struct device *dev = &port->dev;
+ int data_bits, stop_bits, parity_type, parity_enable;
+ unsigned cflag, iflag;
+ unsigned long flags;
+ __u8 oldlines;
+ int linechange = 0;
+
+ spin_lock_irqsave(&priv->lock, flags);
+ /* We can't clean this one up as we don't know the device type
+ early enough */
+ if (!priv->termios_initialized) {
+ if (priv->chiptype == CT_EARTHMATE) {
+ tty->termios = tty_std_termios;
+ tty->termios.c_cflag = B4800 | CS8 | CREAD | HUPCL |
+ CLOCAL;
+ tty->termios.c_ispeed = 4800;
+ tty->termios.c_ospeed = 4800;
+ } else if (priv->chiptype == CT_CYPHIDCOM) {
+ tty->termios = tty_std_termios;
+ tty->termios.c_cflag = B9600 | CS8 | CREAD | HUPCL |
+ CLOCAL;
+ tty->termios.c_ispeed = 9600;
+ tty->termios.c_ospeed = 9600;
+ } else if (priv->chiptype == CT_CA42V2) {
+ tty->termios = tty_std_termios;
+ tty->termios.c_cflag = B9600 | CS8 | CREAD | HUPCL |
+ CLOCAL;
+ tty->termios.c_ispeed = 9600;
+ tty->termios.c_ospeed = 9600;
+ }
+ priv->termios_initialized = 1;
+ }
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ /* Unsupported features need clearing */
+ tty->termios.c_cflag &= ~(CMSPAR|CRTSCTS);
+
+ cflag = tty->termios.c_cflag;
+ iflag = tty->termios.c_iflag;
+
+ /* check if there are new settings */
+ if (old_termios) {
+ spin_lock_irqsave(&priv->lock, flags);
+ priv->tmp_termios = tty->termios;
+ spin_unlock_irqrestore(&priv->lock, flags);
+ }
+
+ /* set number of data bits, parity, stop bits */
+ /* when parity is disabled the parity type bit is ignored */
+
+ /* 1 means 2 stop bits, 0 means 1 stop bit */
+ stop_bits = cflag & CSTOPB ? 1 : 0;
+
+ if (cflag & PARENB) {
+ parity_enable = 1;
+ /* 1 means odd parity, 0 means even parity */
+ parity_type = cflag & PARODD ? 1 : 0;
+ } else
+ parity_enable = parity_type = 0;
+
+ switch (cflag & CSIZE) {
+ case CS5:
+ data_bits = 0;
+ break;
+ case CS6:
+ data_bits = 1;
+ break;
+ case CS7:
+ data_bits = 2;
+ break;
+ case CS8:
+ data_bits = 3;
+ break;
+ default:
+ dev_err(dev, "%s - CSIZE was set, but not CS5-CS8\n", __func__);
+ data_bits = 3;
+ }
+ spin_lock_irqsave(&priv->lock, flags);
+ oldlines = priv->line_control;
+ if ((cflag & CBAUD) == B0) {
+ /* drop dtr and rts */
+ dev_dbg(dev, "%s - dropping the lines, baud rate 0bps\n", __func__);
+ priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
+ } else
+ priv->line_control = (CONTROL_DTR | CONTROL_RTS);
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ dev_dbg(dev, "%s - sending %d stop_bits, %d parity_enable, %d parity_type, %d data_bits (+5)\n",
+ __func__, stop_bits, parity_enable, parity_type, data_bits);
+
+ cypress_serial_control(tty, port, tty_get_baud_rate(tty),
+ data_bits, stop_bits,
+ parity_enable, parity_type,
+ 0, CYPRESS_SET_CONFIG);
+
+ /* we perform a CYPRESS_GET_CONFIG so that the current settings are
+ * filled into the private structure this should confirm that all is
+ * working if it returns what we just set */
+ cypress_serial_control(tty, port, 0, 0, 0, 0, 0, 0, CYPRESS_GET_CONFIG);
+
+ /* Here we can define custom tty settings for devices; the main tty
+ * termios flag base comes from empeg.c */
+
+ spin_lock_irqsave(&priv->lock, flags);
+ if (priv->chiptype == CT_EARTHMATE && priv->baud_rate == 4800) {
+ dev_dbg(dev, "Using custom termios settings for a baud rate of 4800bps.\n");
+ /* define custom termios settings for NMEA protocol */
+
+ tty->termios.c_iflag /* input modes - */
+ &= ~(IGNBRK /* disable ignore break */
+ | BRKINT /* disable break causes interrupt */
+ | PARMRK /* disable mark parity errors */
+ | ISTRIP /* disable clear high bit of input char */
+ | INLCR /* disable translate NL to CR */
+ | IGNCR /* disable ignore CR */
+ | ICRNL /* disable translate CR to NL */
+ | IXON); /* disable enable XON/XOFF flow control */
+
+ tty->termios.c_oflag /* output modes */
+ &= ~OPOST; /* disable postprocess output char */
+
+ tty->termios.c_lflag /* line discipline modes */
+ &= ~(ECHO /* disable echo input characters */
+ | ECHONL /* disable echo new line */
+ | ICANON /* disable erase, kill, werase, and rprnt
+ special characters */
+ | ISIG /* disable interrupt, quit, and suspend
+ special characters */
+ | IEXTEN); /* disable non-POSIX special characters */
+ } /* CT_CYPHIDCOM: Application should handle this for device */
+
+ linechange = (priv->line_control != oldlines);
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ /* if necessary, set lines */
+ if (linechange) {
+ priv->cmd_ctrl = 1;
+ cypress_write(tty, port, NULL, 0);
+ }
+} /* cypress_set_termios */
+
+
+/* returns amount of data still left in soft buffer */
+static int cypress_chars_in_buffer(struct tty_struct *tty)
+{
+ struct usb_serial_port *port = tty->driver_data;
+ struct cypress_private *priv = usb_get_serial_port_data(port);
+ int chars = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&priv->lock, flags);
+ chars = kfifo_len(&priv->write_fifo);
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ dev_dbg(&port->dev, "%s - returns %d\n", __func__, chars);
+ return chars;
+}
+
+
+static void cypress_throttle(struct tty_struct *tty)
+{
+ struct usb_serial_port *port = tty->driver_data;
+ struct cypress_private *priv = usb_get_serial_port_data(port);
+
+ spin_lock_irq(&priv->lock);
+ priv->rx_flags = THROTTLED;
+ spin_unlock_irq(&priv->lock);
+}
+
+
+static void cypress_unthrottle(struct tty_struct *tty)
+{
+ struct usb_serial_port *port = tty->driver_data;
+ struct cypress_private *priv = usb_get_serial_port_data(port);
+ int actually_throttled, result;
+
+ spin_lock_irq(&priv->lock);
+ actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;
+ priv->rx_flags = 0;
+ spin_unlock_irq(&priv->lock);
+
+ if (!priv->comm_is_ok)
+ return;
+
+ if (actually_throttled) {
+ result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
+ if (result) {
+ dev_err(&port->dev, "%s - failed submitting read urb, "
+ "error %d\n", __func__, result);
+ cypress_set_dead(port);
+ }
+ }
+}
+
+
+static void cypress_read_int_callback(struct urb *urb)
+{
+ struct usb_serial_port *port = urb->context;
+ struct cypress_private *priv = usb_get_serial_port_data(port);
+ struct device *dev = &urb->dev->dev;
+ struct tty_struct *tty;
+ unsigned char *data = urb->transfer_buffer;
+ unsigned long flags;
+ char tty_flag = TTY_NORMAL;
+ int havedata = 0;
+ int bytes = 0;
+ int result;
+ int i = 0;
+ int status = urb->status;
+
+ switch (status) {
+ case 0: /* success */
+ break;
+ case -ECONNRESET:
+ case -ENOENT:
+ case -ESHUTDOWN:
+ /* precursor to disconnect so just go away */
+ return;
+ case -EPIPE:
+ /* Can't call usb_clear_halt while in_interrupt */
+ /* FALLS THROUGH */
+ default:
+ /* something ugly is going on... */
+ dev_err(dev, "%s - unexpected nonzero read status received: %d\n",
+ __func__, status);
+ cypress_set_dead(port);
+ return;
+ }
+
+ spin_lock_irqsave(&priv->lock, flags);
+ if (priv->rx_flags & THROTTLED) {
+ dev_dbg(dev, "%s - now throttling\n", __func__);
+ priv->rx_flags |= ACTUALLY_THROTTLED;
+ spin_unlock_irqrestore(&priv->lock, flags);
+ return;
+ }
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ tty = tty_port_tty_get(&port->port);
+ if (!tty) {
+ dev_dbg(dev, "%s - bad tty pointer - exiting\n", __func__);
+ return;
+ }
+
+ spin_lock_irqsave(&priv->lock, flags);
+ result = urb->actual_length;
+ switch (priv->pkt_fmt) {
+ default:
+ case packet_format_1:
+ /* This is for the CY7C64013... */
+ priv->current_status = data[0] & 0xF8;
+ bytes = data[1] + 2;
+ i = 2;
+ if (bytes > 2)
+ havedata = 1;
+ break;
+ case packet_format_2:
+ /* This is for the CY7C63743... */
+ priv->current_status = data[0] & 0xF8;
+ bytes = (data[0] & 0x07) + 1;
+ i = 1;
+ if (bytes > 1)
+ havedata = 1;
+ break;
+ }
+ spin_unlock_irqrestore(&priv->lock, flags);
+ if (result < bytes) {
+ dev_dbg(dev,
+ "%s - wrong packet size - received %d bytes but packet said %d bytes\n",
+ __func__, result, bytes);
+ goto continue_read;
+ }
+
+ usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
+
+ spin_lock_irqsave(&priv->lock, flags);
+ /* check to see if status has changed */
+ if (priv->current_status != priv->prev_status) {
+ u8 delta = priv->current_status ^ priv->prev_status;
+
+ if (delta & UART_MSR_MASK) {
+ if (delta & UART_CTS)
+ port->icount.cts++;
+ if (delta & UART_DSR)
+ port->icount.dsr++;
+ if (delta & UART_RI)
+ port->icount.rng++;
+ if (delta & UART_CD)
+ port->icount.dcd++;
+
+ wake_up_interruptible(&port->port.delta_msr_wait);
+ }
+
+ priv->prev_status = priv->current_status;
+ }
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ /* hangup, as defined in acm.c... this might be a bad place for it
+ * though */
+ if (tty && !(tty->termios.c_cflag & CLOCAL) &&
+ !(priv->current_status & UART_CD)) {
+ dev_dbg(dev, "%s - calling hangup\n", __func__);
+ tty_hangup(tty);
+ goto continue_read;
+ }
+
+ /* There is one error bit... I'm assuming it is a parity error
+ * indicator as the generic firmware will set this bit to 1 if a
+ * parity error occurs.
+ * I can not find reference to any other error events. */
+ spin_lock_irqsave(&priv->lock, flags);
+ if (priv->current_status & CYP_ERROR) {
+ spin_unlock_irqrestore(&priv->lock, flags);
+ tty_flag = TTY_PARITY;
+ dev_dbg(dev, "%s - Parity Error detected\n", __func__);
+ } else
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ /* process read if there is data other than line status */
+ if (bytes > i) {
+ tty_insert_flip_string_fixed_flag(&port->port, data + i,
+ tty_flag, bytes - i);
+ tty_flip_buffer_push(&port->port);
+ }
+
+ spin_lock_irqsave(&priv->lock, flags);
+ /* control and status byte(s) are also counted */
+ priv->bytes_in += bytes;
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+continue_read:
+ tty_kref_put(tty);
+
+ /* Continue trying to always read */
+
+ if (priv->comm_is_ok) {
+ usb_fill_int_urb(port->interrupt_in_urb, port->serial->dev,
+ usb_rcvintpipe(port->serial->dev,
+ port->interrupt_in_endpointAddress),
+ port->interrupt_in_urb->transfer_buffer,
+ port->interrupt_in_urb->transfer_buffer_length,
+ cypress_read_int_callback, port,
+ priv->read_urb_interval);
+ result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
+ if (result && result != -EPERM) {
+ dev_err(dev, "%s - failed resubmitting read urb, error %d\n",
+ __func__, result);
+ cypress_set_dead(port);
+ }
+ }
+} /* cypress_read_int_callback */
+
+
+static void cypress_write_int_callback(struct urb *urb)
+{
+ struct usb_serial_port *port = urb->context;
+ struct cypress_private *priv = usb_get_serial_port_data(port);
+ struct device *dev = &urb->dev->dev;
+ int status = urb->status;
+
+ switch (status) {
+ case 0:
+ /* success */
+ break;
+ case -ECONNRESET:
+ case -ENOENT:
+ case -ESHUTDOWN:
+ /* this urb is terminated, clean up */
+ dev_dbg(dev, "%s - urb shutting down with status: %d\n",
+ __func__, status);
+ priv->write_urb_in_use = 0;
+ return;
+ case -EPIPE:
+ /* Cannot call usb_clear_halt while in_interrupt */
+ /* FALLTHROUGH */
+ default:
+ dev_err(dev, "%s - unexpected nonzero write status received: %d\n",
+ __func__, status);
+ cypress_set_dead(port);
+ break;
+ }
+ priv->write_urb_in_use = 0;
+
+ /* send any buffered data */
+ cypress_send(port);
+}
+
+module_usb_serial_driver(serial_drivers, id_table_combined);
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
+
+module_param(stats, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(stats, "Enable statistics or not");
+module_param(interval, int, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(interval, "Overrides interrupt interval");
+module_param(unstable_bauds, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(unstable_bauds, "Allow unstable baud rates");